Percentage reduction valve



Sept. 17, 1957 V. R. BENNETT INVENTOR. 1 E. BEA/N677 BY ,w 2

k I A rronz/vy- United States Patent PERCENTAGE REDUCTION VALVE Vivian Ray Bennett, Los Angeles, Calif., assignor to the United States of America as represented by the Seeretary of the Air Force Application Gctober 21, 1949, Serial No. 122,640

6 Claims. (Cl. 137-64) This invention relates to valves of the type used for delivering oxygen to an oxygen demand mask and more particularly for an oxygen demand mask that is peripherally. sealed by an inflatable bladder in which the'oxygen valve must maintain a pressure at all times higher in the sealing bladder than the mask pressure at a predetermined pressure ratio.

The ever increasing demand for oxygen equipment which permits aircraft flight personnel to attain greater speeds and higher altitudes with safety requires oxygen valves for controlling the oxygen supply to one or more elements or chambers of an oxygen demand mask at different pressures. At altitudes in rarefied air oxygen demand masks must be designed to seal effectively to the wearers face, neck, or shoulders, as the case may be, to avoid the loss of oxygen which oxygen is so valuable to aircraft flight personnel during high altitude flying. One type of oxygen demand mask, that has proved to be satisfactory, utilizes an inflatable bladder fixed to the periphery of the mask such that when the mask is placed on the wearers face and the bladder is inflated the interior of the mask is sealed from the atmosphere and may be pressurized without leakage of oxygen to the atmosphere. To merely inflate the sealing bladder at a pressure higher than the highest expected mask pressure would cause the user unnecessary discomfort during times of low mask pressure. The best means of sealing such masks is to maintain a pressure in the sealing bladder at some predetermined ratio higher than the pressure in the mask.

In accordance with the present invention, a. valvular means is used having a principal inlet and an auxiliary inlet entering an inlet chamber, a mask outlet, and a sealing bladder outlet, adapted for use with a mask. A pressure responsive valve is interposed in a passage between the inlet chamber and the mask outlet which valve is biased closed against inlet chamber pressure by a compression spring. The compression spring is made to vary in its compressive force by a piston that is operative to compress the spring in accordance with the fluid pressure in the inlet chamber acting thereon. The sealing bladder outlet is fluidly connected directly to the inlet chamber such that the sealing bladder of a mask will always be under a pressure equal to that of the valve inlet pressure. The mask outlet pressure will always be lower than the bladder outlet pressure since the inlet chamber pressure effective on the pressure responsive valve to open it must exceed the force of the biasing spring, efiected. by the pressure responsive piston, and the force exerted by the mask outlet pressure effective to' cause valve closing tendencies. As the pressure in the inlet chamber rises, as by an increase in the pressure from the fluid supply source, the pressure in the bladder. outlet will be raised accordingly and the pressure in the mask, outlet will be raised proportionately. In this manner the bladder pressure of .a connected mask would always be proportionately higher than the mask pressure wherein the mask control valve.

pressure vwill be effectively sealed for "all operativepressures of the fluid supply source and no discomfort will be realized by the wearer of the mask since the pressure differential per unit area under the bladder and in the mask will be small.

The principal inlet of the valvular device is used for connection to a main fluid supply, as an oxygen supply line constructed in the interior of an airplane, or the like, and the auxiliary inlet is used for connection to a port able oxygen supply tank or bail-out supply appliance where the valve of the invention is used as an oxygen In order that either of the inlets to the inlet chamber may be used without the use or capping of the other, a check valve is positioned in each inlet to permit the inflow of fluid and to prevent flow outwardly through these openings.

-While the valve device of this invention is particularly adapted for use with an oxygen demand mask of the above noted type, the valve device may find many uses and have general application. Although the valve device of this invention is shown and described for use with an oxygen demand mask by way of illustration, it is to be understood that such an example of the invention is not limiting in the scope of the invention. It is therefore an object of this invention to provide a valve device having inlet means and at least two outlets in which the pressure in one of the companion outlets exceeds the pressure in the other of the companion outletsin a predetermined ratio.

These and other objects and advantages become more apparent as the description proceeds when taken in view of the accompanying drawing, in which: v

Fig. 1 shows a side elevational view of the preferred embodiment of the valve device constructed in accordancewith the invention;

Fig. 2 shows an enlarged sectional view of the valve device of Fig. 1; and

Fig. 3 shows an isometric view partly in section'of certain elements shown in Fig. 2 to clarify the structura relation of these elements. 4

Referring to the drawing, there is shown a valve body 10 having two longitudinally concentric cylindrical chambers 11 and 12 therein joined by an enlarged central chamber 13. The central chamber 13 forms an outlet chamber and is fluidly connected by an outlet passage 14 to a tapped opening 15in the upper side of the valve body 10 which opening has a connector element 16 threaded therein for connecting a flexible tube thereon which, for the purpose of illustrating the present invention, may be a flexible tube connecting the face chamber of an oxygen mask. The lower end of the connector element 16-has a screen 17 held against a shoulder 18 within the passage therethrough by a small snap ring-19 of well known construction. I

The outermost end of the cylindrical chamber 12, which chamber forms an inlet chamber, has the wall thereof threaded at 20 to receive an inlet connector, element 21. The connector element 21 has an outer cylindrical portion 22 with two diametrically opposed pins 23 extending radially outward from the surface thereof to be received by a companion J-slotted connector element (not shown). The inner end of the connector element 21 has a shoulder 24 on which rests a screen 25. The screen 25 is held in'position on the shoulder 24 by a valve seat ring 26 being pressed against the screen overlying the shoulder 24 and held peripherally by an upset portion 27 of the connector element 21. The screen 25 has a central opening in which is supported a hub member 28. Slightly removed from the screen is a circumferential groove in the hub member 28 in which, is sealingly retained the internal periphery of an annular diaphragm valve element 29. The outer peripheral portion of the diaphragm valve element 29 is adapted to rest on the valve seat ring 26 to close the inlet passage to flow through the connector element 21 outwardly from the cylindrical inlet chamber 12.

Another inlet connector element 31 is screw threaded in a threaded opening 32 in the valve body 10, the threaded opening 32 being fluidly connected to the cylindrical inlet chamber 12 by a passage 33. The connector element 31 has a screen 34 and a diaphragm valve member 35 attached to its inner end in the same manner as the screen 25 and valve element 29 are attached to the connector element 21 for the purpose of preventing fluid flow outwardly through this connector element 31. The threaded inlet opening 32 is also fluidly connected to the outermost end of the cylindrical chamber 11 through a passage 36 for the purpose later to be described. The connector element 3 1 is illustrated as being larger and of a different type than the connector element 21 since the valve device is particularly illustrated for use in an oxygen supply system furnishing oxygen to. .a pressure sealed oxygen demand mask. The connector element 31 has a resilient sealing'ring 37 retained in a groove and a snap ring 38. retained in a groove on the outer surface thereof for use in sealing and snap fastening a companion quick disconnect element from an oxygen supply tube of an oxygen supply tank and regulator. device (not shown). Since the connector element 31 is particularly adapted to be connected to the principal fluid supply, the inlet 32 will hereinafter be referred to as the principal or primary inlet 32. The connector element 21 is adapted to be connected to an auxiliary fluid supply source such as a bail-out portable oxygen supply tank (not shown) in this illustration and will hereinafter be referred to as the auxiliary inlet 20.

A secondary outlet connector element 41 is threadedly connected in a threaded outlet opening 42 in fluid communication with the inlet chamber 12. The. connector element 42 has an external cylindrical portion 43 with diametrically opposed pins 44 extending therefrom for. use in attaching a companion quick disconnect element (not shown). In this particular illustration the outlet opening 42 is used to fluidly connect the sealing bladder of an oxygen demand mask for the reasons later to be described.

Within the cylindrical inlet chamber 12 is a sleeve liner 51 that is pressed against the wall of the chamber and abutted against a shoulder 52 at theinner end of this chamber. The threaded opening 20 into which the connector element 21 is threaded is enough larger than the cylindrical inlet chamber 12 to allow the sleeve liner 51 to be pressed into position through this threaded opening when the connector element 21 is removed. Slidable within the sleeve liner 5,1 is a valve member 55 having a cylindrical disk like head portion 56 and integral guide webs 57 extending therefrom. The length of the valve member 55 from the top surface of the head portion 56 to the bottom surface of the guide webs 57 is substantially the same length as the sleeve liner 51. A pin 58 extends across the cylindrical chamber 12 to limit movement of the valve member 55 to a position in which the valve. head 56 is within the sleeve liner 51 to close the passage between the inlet chamber 12 and the central outlet chamber 13. The valve head portion 56 has a raised central portion 59 on the side opposite the guide webs 57 for abutting an actuatable member presently to be described.

Within the cylindrical chamber 11 is a sleeve liner 61 that is held in position between a shoulder 62 at the outer end thereof and a sleeve plate retaining member 63 which plate member 63 is held securely against the sleeve liner 61 by a snap ring 64. The spring plate member 63 has a hub portion 65 centrally thereof and a hole 66 concentric therewith through the plate and the hub portion. Slidable in the hole 66 is a valve actuating plunger 67 having a flanged head portion 68 on the side of the plate member 63. within the cylindrical chamber. The opposite end of the plunger 67 rests against the raised portion. 59 of the valve elementSS. Slidable within the sleeve liner 61 is a cup-shaped piston 71 with the cup portion directed toward the valve actuating plunger 67. Compressed between the piston 71 and the spring plate 63 is a spring 72, and compressed between the piston 71 and the flanged head portion 68 of the valve actuating plunger is a valve spring 73. The piston 71 is limited in its outward movement by the shoulder 62 of the valve body forming a chamber 74 between it and the body member 10 which chamber 74 is in fluid communication with the passage 36. The chamber formed by the piston 71, sleeve 61, and spring plate 63 is open to the atmosphere through V-shaped notches 75 (clearly seen in Fig. 3) cut in the inner end of the sleeve liner 61 opening into a channel or groove 76 formed in the valve body 10. The channel or groove 76 is connected to the atmosphere through a passage 77 in the valve body.

While this valve construction is shown and described using the sleeve liners 51 and 61, the valve wall portions of the cylindrical chambers 11 and 12 may be machined and polished for the. elements slidable therein where use permits. Y

In the operation of the valve device, either the primary fluid inlet 32 or the auxiliary fluid inlet 20 is connected (or both may be connected) to a fluid source of supply under pressure. If only one inlet is used, the other will be blocked by the respective diaphragm valve to prevent loss of the fluid to the atmosphere. For the purpose of illustration let it be assumed that an oxygen supply line is connected to the connector element 31, the face chamber of an oxy en. demand mask is connected to the connector element 16, and the sealing bladder of the oxygen demand mask is connected to the connector element 41. Oxygen under pressure will pass through the diaphragm check valve 35 to pressurize the sealing bladder (not shown), the chamber 74, and the inlet chamber 12 under the valve 55. Pressure of the oxygen under the valve 55 will lift this, valve against the force of the spring 73 to fill the face chamber of the oxygen demand mask (not shown) through the outlet passage 14 until back pressure in the. central or outlet chamber 13 in addition to the force of the spring 73 is slightly greater than the value of the force exerted by the oxygen in the inlet 32 whereupon the valve 55 will close. Variations of the pressure in the central outlet chamber '13, caused by the breathing of a person wearing the mask connected to the connector element 16, effects periodic opening of the valve 55; but the pressure in the outlet chamber 13, and consequently the pressure in the face chamber of the mask, never exceeds the pressure in the outlet passage 42. Pressure in the outlet passage 42 varies only with the supply pressure since the oxygen in this passage 42 is not used or consumed, while the pressure varies in the central outlet chamber in accordance. with; the consumption of the oxygen by-a person wearing the attached mask. The. exhaled air of the mask wearer is; exhausted directly from themaskof'the bladder sealed type noted and the oxygen inlets to the mask face chamber (connected to the valve 10 through the outlet '14) are checked against reverse fluid flow such that the pressure. variations referred to above in the. outlet chamber 13 result from periodic blocking of the outlet passage 14 when the valve is used as an oxygen control valve for oxygen demand masks.

Oxygen inlet pressure active on the outer end surface of the piston 71 will move this piston inwardly against the force of the springs. 72 ,and 73 until the fluid and mechanical force's are equal. An increased compression of the springs 72 and 73 by inward movement of the piston71 causes the force of the spring 73 011 the valve 55 to increase thereby increasing the pressure. differential between the. pressure in the inlet chamber 12 and the pressure in the central outlet chamber 13. The two pressures, in the inlet chamber 12 and the central outlet chamber 13, vary ina ratio as determined by the force of the spring 73 on the. valve 55. By properly proportioning the strength of spring 73 to that of spring 72 and the effective pressure area of the piston 71, any predetermined ratio or percentage of pressure in the outlet 14 to that of the pressure in the outlet 42 can be obtained. As the oxygen supply pressure varies, whether by improper opening of the oxygen regulator or by control for altitude changes, the ratio of inlet chamber pressure to outlet chamber pressure will remain at a constant ratio, limited only by a maximum pressure, this maximum pressure being that which moves the piston 71 to the limit of its inward travel. With a valve device as described above for use to supply oxygen to a bladder sealed oxygen demand mask, the pressure in the sealing bladder is always maintained at a pressure ratio or percentage higher than the mask pressure to effect a pressure tight mask seal and at the same time never having the mask sealing bladder pressure higher than necessary.

Where the valve device of this invention is used in aircraft for aircraft personnel, a bail-out oxygen container will be attached to the clothing of the person equipped with the oxygen system and the container outlet coupled to the connector 21 as is well known by those skilled in the art. The bail-out container has a shut-01f valve which is opened when the wearer of the oxygen equipment sees that bail-out is imminent at high altitude. At the same time of opening the valve of the bail-out container the principal oxygen supply tube is disconnected from connector element 31 and the check valve 35 functions to prevent oxygen from leaking out the inlet 32.

While I have illustrated the preferred embodiment of my invention it is to be understood that various modifications and changes in constructional details and features will be obvious to those skilled in the art without departing from the spirit and scope of my invention andl desire to be limited only by the spirit and scope of the appended claims.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A valve device for providing a percentage reduction in pressure between a pair of outlets comprising; a valve body having inlet means in communication with an inlet chamber, an outlet chamber, an outlet in communication with said outlet chamber; a valve element positioned between said inlet chamber and said outlet chamber for controlling the flow from said inlet chamber to said outlet chamber; a cylindrical chamber extending from said outlet chamber across from said valve element; a piston element slidable in said cylindrical chamber; spring means compressed between said piston and the valve body and valve element; and a chamber on the side of the piston opposite said spring means being in communication with said inlet chamber whereby said piston is moved inwardly in accordance with inlet pressure to increase compression of said spring means to maintain pressure in said outlet in communication with said outlet chamber at a predetermined lower amount than the pressure in said outlet in communication with said inlet for variations in inlet pressure.

2. In a valve device as set forth in claim 1 wherein the inner end of said cylindrical chamber is closed by a spring plate having a central opening therein through which a valve actuatable plunger is slidable forming a variable chamber between said spring plate and said piston, a passage fluidly connecting said variable chamber with the atmosphere, and said spring means comprises two springs, the innermost end of one resting against said spring plate and the innermost end of the other resting against said valve actuatable plunger.

3. A valve device for producing a percentage reduction in pressure between a pair of outlets comprising; a valve body having a principal inlet and an auxiliary inlet in fluid communication with an inlet chamber, an outlet in fluid communication with said inlet chamber, an outlet chamber, and an outlet in fluid communication with said outlet chamber; a cylindrical portion in said valve body connecting said inlet and outlet chambers; a valve ele- 6 ment having a disk-like head portion and guide fin por tions slidable in said cylindrical portion with the head portion thereof adjacent said outlet chamber andsaid guide fin portions adjacent said inlet chamber; a stop for limiting movement of said valve element into said inlet chamber; a pressure responsive movable element in said valve body, said pressure responsive movable element being responsive to fluid pressure in said inlet chamber and having a resilient means acting against said valve 'element biasing said valve element against said stop with a force determined by said pressure responsive means and the fluid pressure in said outlet chamber whereby fluid pressure in said first mentioned outlet is maintained at a predetermined pressure ratio higher than the fluid pressure in said outlet in fluid communication with said outlet chamber.

4. In a valve device as set forth in claim 3 wherein each inlet has a check valve therein to prevent flow outwardly through said inlet from said inlet chamber, and said pressure responsive means is a piston movable in a cylindrical portion of said valve body with the side of said piston opposite to that subjected to inlet pressure being open to the atmosphere.

5. A valve device for producing a percentage reduction in pressure between a pair of outlets comprising; a valve body having inlet means entering into an inlet chamber, an outlet in communication with said inlet chamber, an outlet chamber, an outlet in communication with said outlet chamber, a cylindrical bore connecting said inlet and outlet chambers, and a cylindrical blind bore extending from said outlet chamber concentric with said cylindrical bore; a valve element slidable in said cylindrical bore for controlling the fluid flow from said inlet chamber to said outlet chamber, said valve element having a head portion adjacent said outlet chamber and a guide portion adjacent said inlet portion; a stop member in said inlet chamber for limiting movement of said valve element towards said inlet chamber; a fluid passage connecting said inlet chamber with the end of said cylindrical blind bore; a piston slidable in said cylindrical blind bore; a removable wall separating said outlet chamber from said cylindrical blind bore to form a variable volume chamber between said removable wall and said piston, said removable wall having an opening therethrough and concentric therewith; a valve element actuatable plunger slidable in said opening and engageable with the head portion of said valve element; two springs in said variable volume chamber one of which is compressed between said piston and said removable wall and the other of which is compressed between said piston and said actuatable plunger to bias said valve element to its closed position; and passage means through said valve body placing said variable volume chamber in communication with the atmosphere whereby fluid pressure in said inlet chamber is operative to move said piston inwardly until the forces acting on said piston by the fluid pressure and said springs are equal thereby varying the compressive force of said spring biasing said valve element closed together with the outlet chamber fluid pressure against the opening force on said valve element by fluid pressure in said inlet chamber to provide a higher fluid pressure in said outlet in communication with said inlet chamber than the fluid pressure in said outlet in communication with said outlet chamber at a ratio determined by the relative strength of the two springs.

6. A valve device comprising a valve body having inlet means including an inlet chamber and at least two outlets, at least one of said outlets being associated with an outlet chamber, a valve means interposed and providing a connection between said inlet chamber and said outlet chamber for controlling flow therebetween, the inlet chamber side thereof being directly subject to inlet pressure, pressure responsive means normally abutting said valve means on the outlet chamber side thereof and operatively associated therewith, means for differentially subjecting 7 saiz'i pressure responsive means to inlet pressure and atmospheric pressure "including a resilient biasing means tending to maintain the abutting relation between said valve means and said pressure responsive means and restrict fl'ow through said outlet chamber, and another of '5 said outlets being directly connected to the inlet means whereby a predetermined pressure ratio between the flow in the one of said outlets and the other of said outlets may be maintained.

:References Cited in the file of this patent UNITED STATES PATENTS 

